Machining UP GM 203 (Hm 2471)

UP GM 203 is the EN 60893 designation for the same glass-mat reinforced polyester hard laminate known under DIN 7735 as Hm 2471 - NEMA equivalent GPO-3. It is one and the same product under two standard designations that are both common on the market, not two different materials. The material offers high electrical insulation performance, good resistance to arc tracking and creepage (CTI 600), and is suitable for continuous use up to 130 °C.

We machine precision parts from sheets and rods - sawing, milling, drilling and turning can be carried out cleanly and accurately with sharp, carbide-tipped tools. Because of the abrasive glass-fibre content we use wear-resistant tools and ensure adequate dust extraction. This allows us to reliably produce high-quality insulating and structural parts, from single items to series production.

UP GM 203 (Hm 2471) is worthwhile whenever a highly insulating, mechanically resilient structural material is needed for applications up to 130 °C, for example:

• Insulating and separating parts in low- and medium-voltage switchgear engineering
• Components requiring arc- and tracking-resistance (CTI 600)
• Support insulators and busbar holders
• Structural parts in electrical machine and transformer engineering
• General electrical insulating parts up to 130 °C continuous service temperature

Component price is determined mainly by sheet thickness or rod diameter, dimensions, material utilisation (offcut), machining effort and batch size. UP GM 203 (Hm 2471) falls in the mid-price segment of technical insulating laminates. We are happy to quote binding prices on request based on your drawing.

UP GM 203 (Hm 2471) is not declared suitable for direct food contact. For continuous use above approximately 130 °C, or particularly high mechanical loading, the upgraded grade UP GM 204 (Hm 2472) is the better choice. The thermoset material is also unsuitable for non-machining forming or welding processes.

An honest assessment, and how the disadvantages can be mitigated in practice:

• Advantage: High electrical insulation performance
• Advantage: Good resistance to arc tracking and creepage (CTI 600)
• Advantage: Thermoset, dimensionally stable
• Advantage: Good machinability
• Advantage: Self-extinguishing (UL 94 V-0)
• Disadvantage: Not declared suitable for direct food contact
• Disadvantage: Continuous use limited to approx. 130 °C
• Disadvantage: Glass-fibre content is abrasive, increased tool wear
• Disadvantage: Cannot be formed or welded (thermoset)
• Disadvantage: Mechanically less resilient than UP GM 204 (Hm 2472)
• Practical tip: UP GM 203 (Hm 2471) is the right choice for electrical insulating and structural parts with high requirements for tracking and arc resistance up to 130 °C continuous service temperature. If a higher limiting temperature or higher mechanical strength is required, UP GM 204 (Hm 2472) is the better choice.